Gravitational force is never truly zero. If it has mass, it is pulling at you, though it may be so close to zero that you don’t realize it.

  • radix@lemmy.world
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    8 months ago

    Any given star is constantly emitting an unimaginably large, but finite, number of photons. A tiny few of them travel tens to hundreds of (Earth) years, only to end their journey in your eyeballs.

    • NOT_RICK@lemmy.world
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      8 months ago

      Even crazier when you consider how long that photon bounced around inside the star before escaping out into space

      • LostXOR@fedia.io
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        8 months ago

        Technically the photon is being absorbed and re-emitted inside the star, so it’s not exactly the same photon.

        • intensely_human@lemm.ee
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          8 months ago

          A “photon” is basically just the universe producing a new field in response to an existing one, repeatedly. So photons travel through space in much the same way: they are absorbed and emitted by successive regions of space, with each region being the photon’s wavelength in size.

            • intensely_human@lemm.ee
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              8 months ago

              Can you describe exactly how it is wrong, or is it just a feeling? Are you not familiar with the structure of an electromagnetic wave?

              • Feathercrown@lemmy.world
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                8 months ago

                I’m familiar with the structure, but don’t the electrical and magnetic waves smoothly translate across space? They aren’t “absorbed and emitted by successive regions of space”, right?

                • intensely_human@lemm.ee
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                  8 months ago

                  If you graph the electric field strength along a photon’s flight path, there are points where it is zero. Same for the magnetic field strength.

                  The energy of the photon is transformed continuously between electric and magnetic field potential, and if you consider either of those signals the energy is coming into and going out of that medium repeatedly.

                  Because each of those non-zero periods of field potential happens in a particular spot in space (those fields don’t move; they grow and fade in sequence), I’m saying that region of space has absorbed the photon.

                  Of course, you know, particle wave duality. So in some ways they travel smoothly as well.

  • kometes@lemmy.world
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    8 months ago

    Technically correct, but the gravity from stars is dwarfed by the gravity from yo momma.

  • Nephele Konstantatou@lemmy.world
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    8 months ago

    While that’s technically true, it’s good to note that this doesn’t excuse astrology, which is based on the false fact that the gravity of celestial bodies influences our decisions in everyday life. The gravity of you Karen influences my “daily life” more than these celestial bodies and especially your belief in astrology. 😄

    • Dasus@lemmy.world
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      8 months ago

      While you are affected by gravity, it’d have less of an effect than other things.

      For instance we can scientifically show your birth date does influence your personality, as long as you don’t live on the equator.

      The further North/South you go, the more pronounced the effect becomes.

      That is to say that from large samplings, you can see that extroverted traits are more common with babies born in Spring (in the Northern hemisphere), while introversion is more associated with being born in autumn.

      That ofc doesn’t mean that a person who was born in November will automatically be less extroverted than one born in March, but if you pick two random people from those groups, it’s X% more likely that it is so.

      Astrology is complete fucking bullshit though.

      • Treczoks@lemmy.world
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        8 months ago

        Astrology is complete fucking bullshit though.

        I know. That’s why I added the “/s” tag.

        • Dasus@lemmy.world
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          8 months ago

          I was just pointing that out because me saying birth months can affect personality isn’t me validating any aspect of astrology.

          Just wanted to make sure no-one thinks I’m trying some feeble defense of it.

  • flakpanzer@lemmy.world
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    8 months ago

    Wait, I thought gravity is not a “force” but the curvature of spacetime, so at some point the curvature gotta end or be disturbed by some other source nearby, right? A star so far away is not exerting any “force” on me as I already have two massive objects Earth and Sun twisting the spacetime around me so much. I could however be getting some gravitational waves from that star but not sure how strong they’d be or if they reach me at all (again given Sun and Earth).

    (NOTE: I’m an engineer not a physicist so my understanding could all be wrong)

    • LostXOR@fedia.io
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      8 months ago

      You’re partially right. Gavity has infinite range, so a distant star does exert some force on you. And that force is present regardless of other gravitational fields like the Earth or Sun. However it’s many orders of magnitude weaker than the force from the Earth and Sun so it’s pretty much irrelevant.

    • mumblerfish@lemmy.world
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      8 months ago

      Eh. It’s not really a definite distinction. Even in GR you formulate effective potentials and the gradient on those potentials are still called forces. Then, what is a force on microscopic scale? It is the exchange of force mediators, like photons. If gravitons exists, then there is even a similar framework for defining a force on a microscopic level for electromagnetism as well as gravity. Furthermore, electromagnetism (qed) also has an interpretation as a curvature, as it is a gauge theory, just not a curvature of physical spacetime, and that does not disqualify if from being called a “force”.

    • Björn Tantau@swg-empire.de
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      8 months ago

      With gravity wave detectors we are able to measure gravitational waves from two merging black holes distorting space-time even here on earth. The distortion is less than the width of the nucleus of an atom.